The present invention relates to an aseismatic structure of an indicating lamp installed in an automatic machine, a robot, a production line, a parking lot or the like and used sending various signals for representing for example, that there is a shortage of materials, that work is jamming or that no parking place is available.
This type of indicating lamp is installed for improving safety of users or workers and alerting a need for maintenance of automatic machines and equipment by directing light of one or a plurality of colors to the surroundings as signals, thereby to call a user's safety or maintenance problem to the attention and guide the users.
The above described indicating lamp has a mounting pole so as to be simply installed in any place and is firmly fixed by a screw using a fixture attached to the end of this mounting pole.
However, there has been heretofore particularly provided no indicating lamp having an aseismatic structure. Therefore, if vibration is frequently produced in a place where the indicating lamp is attached, the vibration is received by the indicating lamp, and causes the structure of the indicating lamp to loosen and its electric lamp to blow out.
An attempt to introduce an aseismatic structure into this type of indicating lamp has been made. FIGS. 6 and 7 are diagrams showing a conventional aseismatic structure. In FIG. 6, A denotes a mounting pole of an indicating lamp, and A2 denotes a fixture. The fixture A2 is elastically and removably supported on the mounting pole A by a spring A1. This aseismatic structure is exposed to the exterior and can be directly viewed. In FIG. 7, A denotes an internal chassis of the indicating lamp, and A4 denotes an external cover of the indicating lamp. A rubber bushing A3 is interposed between the internal chassis A and the external case A4.
Furthermore, another aseismatic structure using an electric lamp of aseismatic specification as a light source has been known.
In the above described aseismatic structure shown in FIGS. 6 and 7, the vibration damping effect is obtained utilizing the natural elasticity of the elastic material of members A1 and A3. However, the vibration damping effect often varies due to uneven quality of the elastic material. In addition, the resonance phenomenon occurs at a particular oscillation frequency, which causes the electric lamp to be blown out.
Additionally, the use of an electric lamp of aseismatic specification is not an effective solution because vibration itself is not absorbed. More specifically, a failure due to vibration occurs in a portion other than the electric lamp. In addition, at the time of a strong vibration, the electric lamp is blown out.
Furthermore, an aseismatic structure portion is exposed to the external air. Accordingly, an aseismatic structure formed of elastic material such as rubber is degraded by the external environmental factors such as oil dust in factories. Consequently, the lifetime of the indicating lamp itself may be shortened.